Retractable utility knife



FIG. 1 is a top perspective view of an embodiment of the claimed design;

FIG. 2 is front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a bottom perspective view thereof.

The broken lines depict portions of the retractable utility knife in which the design is embodied that are not considered part of the claimed design. 

CLAIM We claim the ornamental design for a retractable utility knife, as shown and described. 